C.J. Bakker

On the Brownian motion in electric resistances

This note deals with the way in which the well known expression for the voltage fluctuations of a conductor Δ V 2 = 4kTℜ . Δv can be derived by very general statistical considerations. Moreover it deals with the influence of the collision frequency of the electrons. In the latter case Boltzmann and Fermi statistics are applied.

Fluctuations and electron inertia

Abstract By an inductive action the shot effect in radio tubes gives rise to fluctuating displacement currents to grids, which are maintained at a negative potential with respect to the cathode, so that no electrons can reach them. In two different types of radio tubes the fluctuating currents in the control grid-cathode lead have been investigated experimentally and theoretically. The agreement between theory and experiment is satisfactory.

On vacuum tube electronics

Summary The effect of the transit time of the electrons ought to be taken into account for a description of the performance of vacuum tubes at high frequencies. In this paper experiments on this subject are described Theoretical considerations are given. The agreement of the experimental and theoretical results is satisfactory.

Amplification of small alternating tensions by an inductive action of the electrons in a radio valve

Summary The possibility of amplification is investigated both theoretically and experimentally when the anode is kept negative, so that the electrons in a thermionic valve cannot reach this anode, but approach it sufficiently near to induce considerable charges. The influence of the transit times is taken into account. The agreement of theory and experiment is satisfactory.

On the number of neutrons emitted by a radium-beryllium source

Resume On a mesure la quantite des neutrons emis par une source Radium-Glucinium. Cette quantite monte a 2,1.104 neutrons par milli-Curie de Radium.

On the influence of the non linearity of the characteristics on the frequency of dynatron and triode oscillators

Summary The theory of dynatron (secondary emission tube) and triode oscillators based on the non linearity of the characteristics, has been developed to a great extent by Van der Pol and after him by several others. In the present paper formulae, based on this work, and suitable for experimental verification are given for the amplitude and frequency. The results of the experimental investigations are in good agreement with the theoretical formulae given.